Power Line Communication Design question..

Sep 10, 2005 6 Replies

Hi, i'm currently developing a prototype power line modem. I have a question.



Lets say an indoor power line network. There are N number of sockets. PC A is plugged into socket 1 and PC B is plugged into socket 2. When PC A starts transmitting to B, how does the signal know which socket is PC B plugged into? how does the signal know which socket to propagate to? Or does the signal spreads out to every outlet?



I try to be polite, but you _really_ need to study a lot about signal propagation in various wired systems and also about cable radiation into the environment !

The signal will propagate from the transmitter all over the mains phase wire and might be receivable (any security issues here ?) by anybody connected to that same phase wire.

What happens, if the sockets are in the different phase (the 220/380 or 230/400 V three phase system used by most civilised countries or the antiphase 110/220 V system used by the US) ?

Paul

Personal opinion: DON'T!

The power wiring of a house resembles the very first radio antennas by Messrs. Marconi and Popov. How on earth would the radio frequency signal now understand to not radiate?

The phone lines or Ethernet cables are totally different beasts from the usual power wiring: the cables are well twisted together with a controlled wave impedance.

A radio frequency signal travels in the insulation between the forward and return conductors, and this is why the cabling matters.

Besides, there are plenty of RF hindrances in a normal low-voltage power wiring, the 0.1 uF capacitors across each fluorescent light as an example. A cap of this size is a short circuit for the RF signal.

Tauno Voipio tauno voipio (at) iki fi

With all due respect: if your level of expertise doesn't allow you to answer these questions yourself, you're obviously in *way* over your head. Please, drop this project _immediately_. If you don't, you're likely to endanger yourself or others, and you're *certain* to break all kinds of rules about radio frequency emissions, workplace safety and other things.

Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de) Even if all the snow were burnt, ashes would remain.

Look at Renesas. They have a line of MCUs that supports communication over power lines:

Regards Anton Erasmus

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